Polymer solid electrolytes, methods of making, and electrochemical cells comprising the same

ABSTRACT

The present invention generally relates to various polymer solid electrolyte materials suitable for various electrochemical devices and methods for making or using the same. Certain embodiments of the invention are generally directed to solid electrolytes having relatively high ionic conductivity and/or other mechanical or electrical properties, e.g., tensile strength or decomposition potential. Certain aspects include a polymer, a plasticizer, and an electrolyte salt. In some cases, the polymer may exhibit certain structures such as: 
                         
where R 1  can be one of the following groups:
 
                         
where n is an integer between 1 and 10000, m is a integer between 1 and 5000, and R 2  to R 6  are each independently selected from the group consisting of hydrogen, methyl, ethyl, phenyl, benzyl, acryl, epoxy ethyl, isocyanate, cyclic carbonate, lactone, lactam, and vinyl; and * indicates a point of attachment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.16/554,541, filed Aug. 28, 2019, now U.S. Pat. No. 11,302,960, which isa continuation-in-part of U.S. Ser. No. 16/240,502, filed Jan. 4, 2019,now U.S. Pat. No. 11,335,950, which claims the benefit of U.S. Ser. No.62/757,133, filed Nov. 7, 2018, each of which is incorporated herein byreference in its entirety.

FIELD

The present invention generally relates to various polymer solidelectrolyte materials suitable for electrochemical devices such asbatteries, capacitors, sensors, condensers, electrochromic elements,photoelectric conversion elements, etc.

BACKGROUND

Accompanying the rise of energy densities of lithium-ion batteries(LIBs) and the expansions of scale, finding a solution to the safetyconcerns of LIBs becomes more important for LIB development. Safetyissues existing in LIBs may arise from the use of mixed flammablesolvents such as carbonate/ether as solvent systems, which, in the caseof overcharging, short-circuiting, over-heating, etc. can lead toserious accidents from LIBs catching on fire, burning or even exploding,etc.

SUMMARY

The present invention generally relates to various polymer solidelectrolyte materials. The subject matter of the present inventioninvolves, in some cases, interrelated products, alternative solutions toa particular problem, and/or a plurality of different uses of one ormore systems and/or articles.

In one aspect, the present invention is generally directed to an articlecomprising a polymer comprising a product of a crosslinking reactionincluding a polymer selected from the group consisting of:

where R₁ comprises a structure selected from the group consisting of:

where n is an integer between 1 and 10,000, inclusive; where m is aninteger between 1 and 5,000, inclusive; where R₂, R₃, R₄, R₅, and R₆ areeach independently selected from the group consisting of:

and where * indicates a point of attachment.

In another aspect, the present invention is generally directed to amethod of making a polymer solid electrolyte. In one set of embodiments,the method includes mixing a composition comprising a polymer with asolvent to form a slurry, removing the solvent, and curing the slurry toform a solid electrolyte. In some cases, the polymer comprises astructure selected from the group consisting of:

where R₁ comprises a structure selected from the group consisting of:

where n is an integer between 1 and 10,000, inclusive; where m is aninteger between 1 and 5,000, inclusive; where R₂, R₃, R₄, R₅, and R₆ areeach independently selected from the group consisting of:

and where * indicates a point of attachment.

In another aspect, the present invention encompasses methods of makingone or more of the embodiments described herein, for example, polymersolid electrolyte materials. In still another aspect, the presentinvention encompasses methods of using one or more of the embodimentsdescribed herein, for example, polymer solid electrolyte materials.

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1 illustrates mechanical performance test curves of polymer solidelectrolyte according to one embodiment of the invention;

FIG. 2 illustrates an ionic conductivity curve of a polymer solidelectrolyte of another embodiment of the invention;

FIG. 3 illustrates certain chemical structures of polymers, inaccordance with some embodiments of the invention;

FIG. 4 illustrates ionic conductivity curves of the polymer solidelectrolyte of certain embodiments of the invention;

FIG. 5 is a schematic for synthesizing a polymer in accordance with oneembodiment of the invention;

FIG. 6 is a schematic for synthesizing a polymer in accordance withanother embodiment of the invention;

FIG. 7 is a schematic for synthesizing a comparative example;

FIG. 8 is illustrates capacity retention curves, in one embodiment; and

FIG. 9 illustrates an ionic conductivity curve, in another embodiment.

DETAILED DESCRIPTION

The present invention generally relates to various polymer solidelectrolyte materials suitable for various electrochemical devices andmethods for making or using the same. Certain embodiments of theinvention are generally directed to solid electrolytes having relativelyhigh ionic conductivity and/or other mechanical or electricalproperties, e.g., tensile strength or decomposition potential. Certainaspects include a polymer, a plasticizer, and an electrolyte salt. Insome cases, the polymer may exhibit certain structures such as:

where R₁ can be one of the following groups:

where n is an integer between 1 and 10000, m is a integer between 1 and5000, and R₂ to R₆ can each independently be one of the followingstructures:

In addition, certain embodiments are directed to compositions for usewith polymer solid electrolytes, batteries or other electrochemicaldevices comprising such polymer solid electrolytes, and methods forproducing such polymers. In some cases, the incorporation of urea orcarbamate functional groups with UV crosslinking can be used to improvemechanical properties and/or electrochemical performance. In certainembodiments, some polymer solid electrolytes may be used to achievesafer, longer-life lithium batteries. The electrolytes may exhibitbetter ionic conductivity, and lithium ions may be conducted fasterand/or more efficiently. These properties may benefitcharging/discharging rate performances. In addition, the improveddecomposition potential of the polymer materials may provide enhancedstability in a solid state electrolyte, which may provide forlonger-life and/or higher voltage lithium batteries.

Thus, in some aspects, the present invention is generally directed to anelectrochemical cell, such as a battery, comprising a polymer solidelectrolyte material such as those discussed herein. In one set ofembodiments, the battery is a lithium-ion battery, such as a lithium-ionsolid-state battery. The electrochemical cell may also comprise ananode, a cathode, a separator, etc. Many of these are availablecommercially. The polymer solid electrolyte material may be used as theelectrolyte of the electrochemical cell, alone and/or in combinationwith other electrolyte materials.

One aspect, for instance, is generally directed to solid electrolytescomprising certain polymers that can be used within electrochemicaldevices, for example, batteries such as lithium-ion batteries. Suchelectrochemical devices will typically include one or more cells,comprising an anode and a cathode, separated by an electrolyte Incomparison to liquid electrolytes, solid polymer electrolytes may belightweight and provide good adhesiveness and processing properties.This may result in safer batteries and other electrochemical devices. Insome cases, the polymer electrolyte may allow the transport of ions,e.g., without allowing transport of electrons. The polymer electrolytemay comprise a polymer and an electrolyte. The electrolyte may be, forexample, a lithium salt, or other salts such as those discussed herein.

Certain embodiments of the invention are generally directed to solidelectrolytes having relatively high ionic conductivity and othermechanical or electrical properties, e.g., tensile strength ordecomposition potential. In some cases, for example, a polymer mayexhibit improved properties due to the addition of functional groupssuch as urea and/or carbamate moieties within the polymer, e.g., withinthe backbone structure of the polymer. In some cases, the urea and/orcarbamate moieties may be crosslinked together, and/or to otherpolymers, e.g., as described herein.

Without wishing to be bound by any theory, it is believed that groupssuch as urea, urethane, or carbamate contain both hydrogen bond donorsand acceptors, which may lead to improvements in properties such asmechanical and/or electrochemical properties, e.g., as discussed herein.For instance, urea linkers with rigid bonding may help to improvemechanical strength. In addition, the hydrogen bonds may help todissociate lithium salts, which may lead to improved ionic conductivity.

In some embodiments, groups such as urea, urethane, or carbamate may bepresent in the backbone of the polymer, for example, as a linker betweena middle polymeric fragment and two acrylic ends. The urea and/orcarbamate may be provided within the polymer using differentcombinations of functional groups, such as amine and carbamate, oralcohol and isocyanate, during formation of the polymer. Such groups maybe present next to each other, and/or some of the groups may beseparated by spacer groups, e.g., between the urea and/or carbamate, andan acrylate.

Non-limiting examples of polymers containing urea and/or carbamatemoieties include the following structures:

In these structures, R₁ may be selected to allow complexation with saltsor ions, e.g., to produce a polymer/salt complex that can act as anelectrolyte. For example, R₁ may include charged moieties, and/ormoieties that are uncharged but are readily ionizable to produce acharge, e.g., at acidic or alkaline pH's (for instance, at pH's of lessthan 5, less than 4, less than 3, or less than 2, or greater than 9,greater than 10, greater than 11, or greater than 12). Specific examplesof R₁ include, but are not limited to, the following (where * indicatesa point of attachment):

In addition, in some cases, 2, 3, 4, or more of the following may bepresent simultaneously within the R₁ structure, e.g., as copolymers. Forexample, they may be present in alternating, block, random or othercopolymer structures to define the R₁ moiety. In some cases, 2, 3, 4, ormore polymers may be present, and in some cases may be crosslinkedtogether, e.g., as discussed herein.

In these structures n and/or m (as applicable) may each be an integer.In some cases, n and/or m may each be less than 100,000, less than50,000, less than 30,000, less than 10,000, less than 5,000, less than3,000, less than 1,000, less than 500, etc. In certain cases, n and/or mmay be at least 1, at least 3, at least 5, at least 10, at least 30, atleast 50, at least 100, at least 300, at least 500, at least 1,000, atleast 3,000, at least 5,000, at least 10,000, at least 30,000, at least50,000 etc. Combinations of any of these ranges are possible; asnon-limiting examples, n may be an integer between 1 and 10000, m may bean integer between 1 and 5000, n may be an integer between 1000 and5000, m may be an integer between 500 and 1000, etc.

In these structures R₂, R₃, R₄, R₅, and R₆ may each be independentlychosen (as applicable) to make the polymers symmetric or non-symmetric.Examples of R₂, R₃, R₄, R₅, and R₆ include, but are not limited to, oneof the following structures:

Other examples of R₂, R₃, R₄, R₅, and R₆ include, but are not limitedto, an acrylate, an ethylene oxide, an epoxy ethyl group, anisocyanates, a cyclic carbonate, a lactone, a lactams, a vinyl group(CH₂═CH—), or a vinyl derivative (i.e., where 1, 2, or 3 of the H's inthe CH₂═CH— structure have been replaced by an F or a Cl). Non-limitingexamples of cyclic carbonates include ethylene carbonate, propylenecarbonate, fluoroethylene carbonate, etc. In addition, it should beunderstood that these endgroups are provided by way of example only. Ingeneral, the endgroups are not critical, as they typically would notaffect performance in a significant way.

In addition, in one set of embodiments, functional groups such as ureaand/or carbamate may be crosslinked together, e.g., as described herein.For example, such functional groups may be crosslinked together using UVlight, thermoforming or exposure to elevated temperatures (e.g., betweentemperatures of 20° C. and 100° C.), or other methods including thosedescribed herein. In some cases, the incorporation of urea or carbamatefunctional groups can improve mechanical properties, electrochemicalperformances, or the like, such as relatively high ionic conductivities,ion transference numbers, decomposition voltages, tensile strength, orthe like.

In some cases, the degree of crosslinking may be determined. The degreeof crosslinking is generally defined by the ratio between the reactedacrylate groups and the original acrylate groups. The weight or molarpercentage of the polymer in the formulation can be assumed to controlthe degree of crosslinking, assuming that all of the acrylate groupshave been reacted. In some cases, at least 1%, at least 3%, or at least5% of the polymer has been crosslinked.

In some cases, solid electrolytes such as those described herein mayprovide certain beneficial properties, such as surprisingly high ionicconductivities, compared to other solid electrolytes. For example, thepolymer solid electrolyte may exhibit ionic conductivities of at least10⁻⁸ S/cm, at least 2×10⁻⁸ S/cm, at least 3×10⁻⁸ S/cm, at least 5×10⁻⁸S/cm, at least 10⁻⁷ S/cm, at least 2×10⁻⁷ S/cm, at least 3×10⁻⁷ S/cm, atleast 5×10⁻⁷ S/cm, at least 10⁻⁶ S/cm, at least 2×10⁻⁶ S/cm, at least3×10⁻⁶ S/cm, at least 5×10⁻⁶ S/cm, at least 10⁻⁵ S/cm, at least 2×10⁻⁵S/cm, at least 3×10⁻⁵ S/cm, at least 5×10⁻⁵ S/cm, at least 10⁻⁴ S/cm, atleast 2×10⁴ S/cm, at least 3×10⁴ S/cm, at least 5×10⁴ S/cm, at least10⁻³ S/cm, at least 2×10⁻³ S/cm, at least 3×10⁻³ S/cm, at least 5×10⁻³S/cm, etc. In one embodiment, for example, the polymer solid electrolytehas ionic conductivity in between 2.1×10⁻⁶ S/cm and 5.2×10⁻⁶ S/cm. Inother embodiments, as examples, the ionic conductivity may be between10⁻⁸ and 10⁻² S/cm, or between 5×10⁻⁵ and 10⁻² S/cm, etc. Withoutwishing to be bound by any theory, it is believed that ionicconductivity is improved because groups such as ureas or carbamatescontain both hydrogen-bond donors and acceptors, which may lead to theimprovements of both mechanical and electrochemical performances due tohydrogen boding. In addition, it is believed that the hydrogen bonds mayhelp to dissociate salts such as the lithium for better ionicconductivity.

In addition, in some embodiments, polymer solid electrolytes such asthose described herein may provide relatively high decompositionvoltages. Polymer solid electrolytes with relatively high decompositionvoltages may be particularly useful, for example, in applications wherehigher voltages are required. In certain cases, the decompositionvoltage of the polymer solid electrolyte may be at least 0.3 V, at least0.4 V, at least 0.5 V, at least 0.6 V, at least 0.7 V, at least 0.8 V,at least 0.9 V, at least 1 V, at least 1.5 V, at least 2 V, at least 2.5V, at least 3 V, at least 3.5 V, at least 3.8 V, at least 4 V, at least4.3 V, at least 4.5 V, or at least 5 V. Decomposition voltages can betested using standard techniques known to those of ordinary skill in theart, such as cyclic voltammetry. Without wishing to be bound by anytheory, it is believed that ureas or carbamates contains rigid sigmabonds between carbon and oxygen or nitrogen. The carbon atom in thestructure is in the highest covalent state with the carbon-oxygen doublebonds, which may help the structure to resist decomposition.

In certain embodiments, polymer solid electrolytes such as thosedescribed herein can provide relatively high ion transference numbers.Generally, such transference numbers measure the fraction of electricalcurrent that is carried by certain ionic species, e.g., lithium ions. Insome cases, relatively higher ion transference numbers can help withdelaying and/or slowing the growth of lithium dendrites, e.g., withinlithium batteries. Thus, in some embodiments, polymer solid electrolytessuch as those described herein may provide lithium transference numbersof at least 0.1, at least 0.15, at least 0.2, at least 0.25 at least0.3, at least 0.35, at least 0.4, at least 0.45, at least 0.5, at least0.55, at least 0.6, at least 0.65, at least 0.7, at least 0.75, at least0.8, at least 0.85, at least 0.9, at least 0.95, etc. In some cases, thelithium transference numbers may be less than 1, less than 0.95, lessthan 0.9, less than 0.85, less than 0.8, less than 0.75, less than 0.7,less than 0.65, less than 0.6, less than 0.55, or less than 0.5.Combinations of any of these are also possible in certain embodiments.For example, the lithium transference number may be between 0.4 and0.65, between 0.45 and 0.6, between 0.3 and 0.7, between 0.42 and 0.64,between 0.1 and 1, or the like. Ion transference numbers can bedetermined using methods such as the Bruce and Vincent method (J.Electroanal. Chem. Interfacial Electrochem., 255:1-17, 1987), or othertechniques known to those of ordinary skill in the art.

In one set of embodiments, polymer solid electrolytes such as thosedescribed herein may exhibit relatively high tensile strengths. Forexample, the tensile strength of the polymer solid electrolytes may beat least 8 MPa, at least 10 MPa, at least 12 MPa, at least 15 MPa, atleast 20 MPa, at least 25 MPa, at least 30 MPa, at least 35 MPa, atleast 40 MPa, at least 45 MPa, at least 50 MPa, etc. In some cases, thetensile strength of the polymer solid electrolytes may be no more than50 MPa, no more than 40 MPa, no more than 30 MPa, etc. In certainembodiments, a polymer solid electrolyte may exhibit tensile strengthswithin any of the ranges, e.g., between 8 MPa and 40 MPa, between 30 MPaand 50 MPa, between 20 MPa and 40 MPa, between 8.2 MPa and 38.4 MPa,between 5 and 500 MPa, between 10 and 500 MPa, etc. Tensile strength canbe tested using standard techniques known to those of ordinary skill inthe art, such as dynamic mechanical analysis.

In one set of embodiments, the polymer solid electrolyte may include aplasticizer, which may be useful for improve processability of thepolymer solid electrolyte, and/or controlling the ionic conductivity andmechanical strength. For example the plasticizer may be a polymer, asmall molecule (i.e., having a molecular weight of less than 1 kDa), anitrile, an oligoether (e.g., triglyme), cyclic carbonate, ionicliquids, or the like. Non-limiting examples of potentially suitableplasticizers include ethylene carbonate, succinonitrile, sulfolane,phosphate, or the like. Non-limiting examples of nitriles includesuccinonitrile, glutaronitrile, hexonitrile, and/or malononitrile.Non-limiting examples of cyclic carbonate include ethylene carbonate,propylene carbonate, fluoroethylene carbonate, etc. Non-limitingexamples of ionic liquids include N-propyl-N-methylpyrrolidiniumbis(fluorosulfonyl)imide or 1-ethyl-3-methylimidazoliumbis(fluorosulfonyl)imide. Other non-limiting examples of plasticizersinclude polymers such as polyethylene oxide, a polycarbonate, apolyacrylonitrile, a polylactic acid, or the like. In some cases, theplasticizer may be a polymer that is relatively hydrophilic, e.g.,having a water contact angle of less than 90°. In addition, the polymermay be free of sulfur.

In some embodiments, an electrolyte salt may be present. These mayinclude alkali metal salts, such as lithium or sodium. Specificnon-limiting examples of lithium salts include LiTFSI, LiFSI, LiBOB,LiPF₆, LiBF₄, LiClO₄, LiAsF₆, LiN(CF₃SO₂)₂, LiC(CF₃SO₂)₃, LiDFOB, LiF,LiCl, LiBr, LiI, Li₂SO₄, LiNO₃, Li₃PO₄, Li₂CO₃, LiOH, lithium acetate,lithium trifluoromethyl acetate, lithium oxalate, etc. Other examplesinclude, but are not limited to, quaternary ammonium salts, quaternaryphosphonium salt, transition metal salts, or salts of protonic acids.Non-limiting examples of protonic acids includedimethyldioctadecylammonium chloride, tetraphenylphosphonium chloride,cobalt sulfate, lithium sulfate, etc.

In addition, other compounds may also be present, such as cathodeprotective agents, anode protective agents, anti-oxidative agents,inorganic additive, etc. Non-limiting examples of inorganic additivesinclude Al₂O₃, SiO₂, SiO_(x), TiO₂, Li₃PS₄, Li₁₀GeP₂S₁₂, Li₇La₃Zr₂O₁₂,Li_(6.4)La₃Zr_(1.4)Ta_(0.6)O₁₂, LiLaTiO₃,Li_(1.3)Al_(0.3)Ti_(1.7)(PO₄)₃, Li_(1.3)Al_(0.3)Ge_(1.7)(PO₄)₃, BaTiO₃,Li₂TiO₃, ZrO₂ etc. An example of a cathode protective agent is LiDFOB(lithium difluoro(oxalato)borate). An example of an anode protectiveagent is fluoroethylene carbonate. An example of an anti-oxidative agentis LiBOB (lithium bis(oxalate)borate). Other similar compounds will beknown by those of ordinary skill in the art. These may be added for avariety of reasons, e.g., to improve other performance metrics, such ascyclability. In some cases, an inorganic additive may be used thatcontains generally electronegative atoms such as oxygen, which mayattract cations. Thus, for example, ions such as Li⁺ can be relocatedrelatively more easily than the anions.

In some cases, the polymer solid electrolyte may exhibit amicrophase-separated structure, such as a network-typemicrophase-separated structure. In some cases, the crosslinked polymerwith may precipitate and form polymer-liquid or polymer solid interface.This can be identified using techniques such as scanning electronmicroscopy using elemental identification.

In certain cases, a polymer, a plasticizer, and an electrolyte salt mayeach present within the electrolyte material at any suitableconcentration. In addition, one or more than one of these may bepresent, e.g., there may be more than one polymer, and/or more than oneplasticizer, and/or more than one electrolyte salt. Other components,such as cathode protective agents, anode protective agents,anti-oxidative agents, inorganic additive, etc. may also be present aswell in some cases.

In one set of embodiments, the polymer may be present at a mole fractionof at least 0.01, at least 0.02, at least 0.027, at least 0.03, at least0.05, at least 0.1, at least 0.11, at least 0.12, at least 0.13, atleast 0.15, at least 0.2, at least 0.21, at least 0.22, at least 0.23,at least 0.25, at least 0.3, and/or no more than 0.3, no more than 0.25,no more than 0.32, no more than 0.22, no more than 0.21, no more than0.2, no more than 0.15, no more than 0.13, no more than 0.12, no morethan 0.11, no more than 0.1, no more than 0.05, no more than 0.03, nomore than 0.02, no more than 0.01, etc.

In some embodiments, the plasticizer can be present at a mole fractionof at least 0.1, at least 0.11, at least 0.12, at least 0.13, at least0.15, at least 0.2, at least 0.22, at least 0.23, at least 0.25, atleast 0.287, at least 0.3, at least 0.31, at least 0.32, at least 0.33,at least 0.35, at least 0.4, at least 0.5, at least 0.6, at least 0.7,at least 0.8, at least 0.9, at least 0.93, at least 0.95, and/or no morethan 0.95, no more than, no more than 0.93, no more than 0.916, no morethan 0.9, no more than 0.8, no more than 0.7, no more than 0.6, no morethan 0.5, no more than 0.4, no more than 0.35, no more than 0.33, nomore than 0.32, no more than 0.31, no more than 0.3, no more than 0.25,no more than 0.32, no more than 0.22, no more than 0.21, no more than0.2, no more than 0.15, no more than 0.13, no more than 0.12, no morethan 0.11, no more than 0.1, etc.

In one set of embodiments, the electrolyte salt may be present at a molefraction of at least 0.01, at least 0.03, at least 0.05, at least 0.1,at least 0.13, at least 0.15, at least 0.2, at least 0.23, at least0.25, at least 0.3, at least 0.33, at least 0.35, at least 0.4, at least0.43, at least 0.45, at least 0.5, at least 0.53, at least 0.55, atleast 0.6, at least 0.63, at least 0.65, at least 0.7, and/or no morethan 0.7, no more than 0.65, no more than 0.63, no more than 0.617, nomore than 0.6, no more than 0.55, no more than 0.53, no more than 0.5,no more than 0.45, no more than 0.43, no more than 0.4, no more than0.35, no more than 0.33, no more than 0.3, no more than 0.25, no morethan 0.23, no more than 0.2, no more than 0.15, no more than 0.13, nomore than 0.1, etc.

Combinations of any of one or more of the above ranges and intervals arealso possible. For example, the composition may include a polymer(including more than one polymer) having a mole fraction between 0.027and 0.200, a plasticizer (including more than one plasticizer) having amole fraction between 0.287 and 0.916, and an electrolyte salt(including more than one electrolyte salt) having a mole fractionbetween 0.04 and 0.617. Without wishing to be bound by any theory, ifthe polymer concentration is too high, the solid electrolyte may berelatively soft, which could be harder to handle; however, if theplasticizer concentration is too high, the solid electrolyte may be verytough, easy to break during handling, and/or may not provide goodadhesion.

Certain aspects of the present invention are generally directed tosystems and methods for producing any of the polymer solid electrolytesdiscussed herein. For example, in one set of embodiments, a polymer maybe produced by reacting various monomers together. Non-limiting examplesof monomers include different combinations of the structures describedherein, for example, methacrylate monomers with different ester groups,such as norbornyl methacrylate. Other examples of esters include, butare not limited to, methyl methacrylate, ethyl methacrylate, butylmethacrylate, 2-aminoethyl methacrylate hydrochloride, glycidylmethacrylate, 2-(diethylamino)ethyl methacrylate, etc.

In some cases, an initiator may be present, e.g., to facilitatepolymerization. For example, the initiator may include a chemicalinitiator, such as Irgacure initiator,2,2′-azobis(2-methylpropionitrile), ammonium persulfate, or otherinitiators known to those of ordinary skill in the art. In some cases,the initiator may be added to have a mole fraction between 0.001 and0.01, or other suitable mole fractions to facilitate polymerization.

In one set of embodiments, the polymer may be mixed with a solvent toform a slurry, which can be cured to form a solid. In addition, in somecases, more than one polymer may be present in the slurry, e.g., a firstpolymer and a second polymer, which may be added to the slurrysequentially, simultaneously, etc. The polymers may each independentlybe polymers such as those described herein, and/or other suitablepolymers.

Non-limiting examples of suitable solvents include solvents such aswater (e.g., distilled water), methanol, ethanol, or other aqueoussolvents. Other examples of solvents include organic solvents such aspyridine, chloroform, or the like. In some cases, more than one suchsolvent may be present. In addition, after formation of the slurry, thesolvent may be removed, e.g., via techniques such as evaporation.

In addition, in some cases, a plasticizer may be present as well, e.g.,such as succinonitrile, ethylene carbonate, sulfolane, trimethylphosphate, or the like. In addition, in some embodiments, anelectrolytic salt may also be present, for example, an alkali metalsalt, such as lithium or sodium. Specific non-limiting examples oflithium salts include LiTFSI, LiFSI, LiBOB, LiPF₆, LiBF₄, LiClO₄,LiAsF₆, LiN(CF₃SO₂)₂, LiC(CF₃SO₂)₃, LiDFOB, LiF, LiCl, LiBr, LiI,Li₂SO₄, LiNO₃, Li₃PO₄, Li₂CO₃, LiOH, lithium acetate, lithiumtrifluoromethyl acetate, lithium oxalate, etc., or other salts such asthose described herein.

In some embodiments, the slurry may be cured to form a film, such as asolid-state film. For instance, the mixture can be formed into a film bycuring, for example, using UV light, thermoforming, exposure to elevatedtemperatures, or the like. For example, curing may be induced usingexposure to UV light for at least 3 min, at least 5 min, at least 10min, at least 15 min, etc., and/or by exposure to temperatures of atleast 20° C., at least 30° C., at least 40° C., at least 50° C., atleast 60° C., at least 70° C., at least 80° C., at least 90° C., atleast 100° C., etc. As an example, a slurry may be coated or positionedon a surface and/or within a mold, and exposed to UV light to cause thepolymer to cure.

In addition, in some cases, during the curing process, at least some ofthe polymers may also cross-link, e.g., as discussed herein, which insome cases may improve mechanical properties and/or electrochemicalperformance. For example, exposure to UV light may facilitate thecross-linking process. As another example, thermal crosslinking may beused.

U.S. Provisional Patent Application Ser. No. 62/757,133, filed Nov. 7,2018, entitled “Polymer Solid Electrolytes,” by Huang, et al., isincorporated herein by reference in its entirety. Also incorporatedherein by reference in their entireties are U.S. patent application Ser.No. 16/240,502, filed Jan. 4, 2019, entitled “Polymer SolidElectrolytes,” by Huang, et al., and International Patent ApplicationSerial No. PCT/US19/12310, filed Jan. 4, 2019, entitled “Polymer SolidElectrolytes,” by Huang, et al.

The following examples are intended to illustrate certain embodiments ofthe present invention, but do not exemplify the full scope of theinvention.

Example 1

This example illustrates the synthesis of a PEG-urethane-diepoxy polymerhaving a general structure:

In this example, 40 mmol of 4,7,10-trioxa-1,13-tridecanediamine (TTDDA;commonly known as polyethylene glycol diamine (PEGDAm)), 200 mmolpyridine and 100 ml CHCl₃ were added to a 250 mL round-bottom flask.These are all generally available commercially; in particular, PEGDAmcan be obtained in a range of molecular weights, corresponding to thenumber of repeat units of polyethylene glycol within the compound. Seealso FIG. 5 .

The mixture was stirred at 0° C. for 5 h, and then a slightly yellowsolution was obtained. 100 ml of 0.1 mol/1 hydrochloric acid was pouredonto the reaction mixture, and the product was collected and washed with200 ml CHCl₃ twice. After drying with MgSO₄, the crude product wasevaporated to become a light brown crude diisocyanate. The product(PEG-diisocyanate or PEGDI) was purified by a silica gel column.

10 mmol PEG-diisocyanate (PEGDI) and (25 mmol) glycidol were reacted at0° C. for 24 h with a 0.1% dibutyltin dilaurate catalyst. The productwas washed with 0.5 M sodium bicarbonate solution. The organic phase wasdried with MgSO₄. After the solvent was evaporated, a light brown crudediisocyanate was obtained. By applying CHCl₃-hexane at a volume ratio of1:4 to 3:2 as an eluent, column chromatography was used to purify theproduct to produce the polymer (PEG-urethane-diepoxy or PEGDEp).

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts (lithiumbis(trifluoromethanesulfonyl)imide, LiTFSI), and plasticizer(succinonitrile, SN) in the ratios described in Table 1 by mechanicalstirring at room temperature in the liquid state.

The above mixture was applied to a PET thin film. In particular, asolid-state polymer electrolyte film was obtained by UV-curing for 5min. Mechanical properties, ionic conductivities, and electrochemicalstabilities of the membrane were determined on the as-processed film, asfollows.

Mechanical property testing was performed with dynamic mechanicalanalysis using a Dynamic Mechanical Analyzer (DMA Q800, TA Instruments).The polymer solid-state membrane was molded into a standard tensile testsample with dimensions of 7 mm×58 mm. The elongation speed was 3 mm/min.

Electrochemical stability testing was performed using cyclic voltammetrymeasurements with an AC impedance analyzer (Interface 1010EPotentiostate, Gamry). Samples with an area of 1 cm² were sealed betweenstainless-steel plate and lithium foil (reference electrode). Theoperating voltage range was from −0.5 to 5.6 V with a scan rate of 10mV/s. The experiment was conducted at room temperature.

Ionic conductivities testing was performed with an AC impedance analyzer(Interface 1010E Potentiostat, Gamry). Samples with an effective area of1 cm² were placed in 2032 coin-type cells. The ionic conductivity wasmeasured in the frequency range of 13 MHz to 5 Hz by a bias voltage of10 mV.

Example 2

This example illustrates the synthesis of a PEG-urea-diepoxy polymerhaving a general structure:

In this example, 40 mmol of 4,7,10-trioxa-1,13-tridecanediamine (TTDDA;commonly known as polyethylene glycol diamine (PEGDAm)), 200 mmolpyridine and 100 ml CHCl₃ were added to a 250 mL round-bottom flask. Themixture was stirred at −10° C. for 10 min, and then 80 ml triphosgene 85mmol in CHCl₃ solution was added to the solution for 10 min at −20° C.The mixture was then stirred at 0° C. for 5 h. A slightly yellowsolution was obtained.

100 ml of 0.1 mol/L hydrochloric acid was added to the reaction mixtureto obtain a two-phase separated liquid mixture. The product wascollected and washed with 200 ml CHCl₃ twice. The moisture in theproduct was removed by adding MgSO₄. After the solvent was evaporated, alight brown crude diisocyanate was obtained. The product(PEG-diisocyanate or PEGDI) was purified by a silica gel column.

Then, 10 mmol PEGDI and 25 mmol glycidyl amine were reacted at 0° C. for24 h with a 0.1% dibutyltin dilaurate catalyst. The product was washedwith 0.5 M sodium bicarbonate solution. The organic phase was dried withMgSO₄. After the solvent was evaporated, a light brown crudediisocyanate was obtained. By applying CHCl₃-hexane at a volume ratio of1:4 to 3:2 as an eluent, column chromatography was used to purify theproduct (PEG-urea-diepoxy or PEGDEp).

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts (lithiumbis(trifluoromethanesulfonyl)imide, LiTFSI), and plasticizer(succinonitrile, SN) in the ratios described in Table 1 by mechanicalstirring at room temperature in the liquid state.

The above mixture was applied to a PET thin film. In particular, asolid-state polymer electrolyte film was obtained by UV-curing for 5min. Mechanical properties, ionic conductivities, and electrochemicalstabilities of the membrane were determined on the as-processed film,using measurement methods and conditions similar to Example 1.

Example 3

This example illustrates the synthesis of decyl-urethane-diepoxy,Polymer B (see FIG. 3 ):

In this structure, n is 5. In this example, 60 mmol of1,10-diaminodecane, 120 mmol pyridine, and 50 ml CHCl₃ were added to a100 ml round-bottom flask. The mixture was stirred at −20° C. for 30min, and then 80 ml triphosgene of 85 mmol in CHCl₃ solution was addedto the solution in 10 min at −20° C. The mixture was then stirred at 0°C. for 12 h. A slightly yellow solution was obtained.

100 ml of 0.1 mol/1 hydrochloric acid was added to the reaction mixtureto obtain a two-phase separated liquid mixture. The product wascollected and washed with 200 ml CHCl₃ twice. The moisture in theproduct was removed by adding MgSO₄. After the solvent was evaporated, alight brown crude diisocyanate was obtained. The product (decyldiisocyanate or DDI) was purified by a silica gel column.

10 mmol DDI and 25 mmol glycidol were reacted at 0° C. for 24 h with a0.1% dibutyltin dilaurate catalyst. The product was washed with 0.5 Msodium bicarbonate solution. The organic phase was dried with MgSO₄.After the solvent was evaporated, a light brown crude diisocyanate wasobtained. By applying CHCl₃-hexane at a volume ratio of 1:4 to 3:2 as aneluent, column chromatography was used to purify the product(decyl-urethane-diepoxy or DDEp).

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts (lithiumbis(trifluoromethanesulfonyl)imide, LiTFSI), and plasticizer (ethylenecarbonate, EC) in the ratios described in Table 1 by mechanical stirringat room temperature in the liquid state.

The above mixture was applied to a PET thin film. In particular, asolid-state polymer electrolyte film was obtained by UV-curing for 5min. Mechanical properties, ionic conductivities, and electrochemicalstabilities of the membrane were determined on the as-processed film,using measurement methods and conditions similar to Example 1.

Example 4

This example illustrates the synthesis of benzene-urethane-diepoxy,Polymer C (see FIG. 3 ):

In this structure, m is 1. In this example, 60 mmol of1,4-diaminobenzene of 120 mmol pyridine and 50 ml CHCl₃ were added to a100 ml round-bottom flask. The mixture was stirred at −20° C. for 30min, and then 80 ml triphosgene of 85 mmol in CHCl₃ solution was addedto the solution in 10 min at −20° C. The mixture was then stirred at 0°C. for 12 h. A slightly yellow solution was obtained.

100 ml of 0.1 mol/1 hydrochloric acid was added to the reaction mixtureto obtain a two-phase separated liquid mixture. The product wascollected and washed with 200 ml CHCl₃ twice. After drying with MgSO₄, acrude product was obtained by solvent evaporation. The product(1,4-benzene diisocyanate or DDI) was purified by a silica gel column.

10 mmol DDI and 25 mmol glycidol were reacted at 0° C. for 24 h with a0.1% dibutyltin dilaurate catalyst. The product was washed with 100 ml0.5 M sodium bicarbonate solution. The organic phase was dried withMgSO₄. After the solvent was evaporated, a light brown crudediisocyanate was obtained. By applying CHCl₃-hexane at a volume ratio of1:4 to 3:2 as an eluent, column chromatography was used to purify theproduct (benzene-urethane-diepoxy or DDEp).

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts (lithiumbis(trifluoromethanesulfonyl)imide, LiTFSI), and plasticizer(succinonitrile, SN) in the ratios described in Table 1 by mechanicalstirring at room temperature in the liquid state.

The above mixture was applied to a PET thin film. In particular, asolid-state polymer electrolyte film was obtained by UV-curing for 5min. Mechanical properties, ionic conductivities, and electrochemicalstabilities of the membrane were determined on the as-processed film,using measurement methods and conditions similar to Example 1.

Comparison Examples 1 and 2

The polymer for comparison 1 is:

The polymer in comparison 2 is Polymer A (see also FIG. 3 ):

These polymers can be obtained commercially.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts (lithiumbis(trifluoromethanesulfonyl)imide, LiTFSI), and plasticizer in theratios described in Table 1 by mechanical stirring at room temperaturein the liquid state. In Comparison Example 1, succinonitrile (SN) wasused. In Comparison Example 2, ethylene carbonate (EC) was used.

The above mixture was applied to a PET thin film. In particular, asolid-state polymer electrolyte film was obtained by UV-curing for 5min. Mechanical properties, ionic conductivities, and electrochemicalstabilities of the membrane were determined on the as-processed film,using measurement methods and conditions similar to Example 1.

Example Summary

Table 1 illustrates characterization data of the polymer solidelectrolytes shown in Examples 1-4 and Comparison Examples 1 and 2.

TABLE 1 Molar ratio of polymer, plasti- Ionic Decom- cizer, TensileCond- position Example/ Lithium Plasti- lithium strength uctivityVoltage Comparison salt cizer salt (MPa) (S/cm) (V) Example 1 LiTFSI SN1:3:1 19.2 3.3 × 10⁻⁴ 4.3 Example 2 SN 30.8 8.2 × 10⁻⁵ 4.4 Example 3 EC17.8 3.7 × 10⁻⁴ >4.6 Example 4 EC 29.7 6.2 × 10⁻⁴ >4.6 Comparison SN 8.64.9 × 10⁻⁴ 4.0 Example 1 Comparison EC 8.6 2.8 × 10⁻⁴ 4.0 Example 2

In these examples, the different plasticizers were compared(succinonitrile, SN vs. ethylene carbonate, EC), and the different R¹groups were compared (a C—C—O hydrophilic backbone vs. a C—C hydrophobicbackbone). Compared to Comparison Examples 1 and 2, by introducing acarbamate group (Examples 1, 3, and 4) or a urea group (Example 2) intothe polymer, the tensile strength, ionic conductivity, and degradationvoltage of the polymer solid electrolyte all were enhanced.

Example 5

This example illustrates the synthesis of a polyethyleneglycol-bis-carbamate polymer having a general structure. See also FIG. 6:

In this example, a round bottom flask was filled with poly(ethyleneglycol) diamine (40 mmol, Mn=2000, PEG2000DAm), propylene carbonate (85mmol), and chloroform (100 ml). The mixture was stirred for 24 hours at20° C. The resultant reaction mixture solution was washed with water(100 ml). The water fraction was separated and re-extracted by twoportions of chloroform (100 ml). All of the organic phases were combinedand dried with magnesium sulfate. The dried organic solution wasfiltered and concentrated using a rotary evaporator. A crude mixture ofpolyethylene glycol-bis-carbamate (PEGBC2000) was formed as a yellowsolid. The crude product was further purified by silica columnchromatography.

The PEGBC2000 (10 mmol) obtained from last step was mixed withmethacrylic anhydride (25 mmol) in a beaker in an ice-cold bath.4-dimethylaminopyridine (0.1%, DMAP) was used as a catalyst, withhydroquinone (0.1%, HQr) as an inhibitor, and triethylamine (50 mmol,TEA). The reaction was carried out for 24 hours. The crude reactionmixture was neutralized and washed with 0.5 M aqueous sodium bicarbonatesolution. Then, the aqueous phase was washed twice with chloroform. Allof the organic phases were combined and dried with magnesium sulfate.The dried organic solution was filtered and concentrated using a rotaryevaporator. A crude mixture of polyethylene glycol-bis-carbamatedimethacrylate (PEGBC2000DA) was obtained as a yellow solid. The crudeproduct was further purified by silica column chromatography with aneluent of mixed solvent of chloroform and n-hexane in a volume ratio ofbetween 1:4 and 3:2.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts, and plasticizer in the amountsand ratios described in Table 2 by mechanical stirring at roomtemperature in the liquid state.

The products obtained via these methods were mixed with polymers,lithium salts, initiators, and inorganic fillers in certain molarratios. The mixtures were blended into a single-phase liquid by stirringat room temperature. The obtained mixture was solidified into a solidstate electrolyte. Details of the lithium salt, plasticizers, and othercomponents are listed in Table 3.

The liquid and viscous mixture mentioned above was directly applied ontoa polyethylene terephthalate (PET) substrate. A 5-minute UV exposure wasapplied to the coating. Mechanical properties (e.g., tensile strengthand tensile elongation), ionic conductivities, and electrochemicalstabilities were determined. The measurement methods and conditions aresimilar to Example 1. Results are listed in Table 2 and Table 3.

By comparing Example 5-19, 5-20, and 5-2, certain inorganic additiveswere demonstrated as improving tensile strength and/or ion transferencenumbers. The inorganic additive may provide certain advantages where theurea and/or carbamate are present. For instance, in Example 5, the teststructures all use carbamate. The relatively higher ion transfer numbersmay help with delaying the growth of lithium dendrites. In some cases,palliating polarization during charge and discharge may further reducethe internal electrical resistance.

FIG. 5 shows electrochemical impedance spectroscopy of solid stateelectrolytes fabricated by the polymer in Example 5. The formulation isshown in Table 2, Example 5-2. The far left cross between the semi-cycleand the line Y=0 shows the bulk resistance of the solid stateelectrolyte membrane. The ionic conductivity can be calculated with theknown thickness and area the membrane.

TABLE 2 Molar ratio of polymer: plasti- Elongation Ionic Decom- cizer:Tensile at Con- position Lithium Plasti- lithium strength breakductivity Voltage Example Salt cizer salt (MPa) (%) (S/cm) (V) Example5-1 LiTFSI SN 1:1:3 19.2 8.60 × 10⁻⁴ >4.6 Example 5-2 LiPF₆ EC 1:1:318.3 1.12 × 10⁻³ >4.6 Example 5-3 LiPF₆ SN 1:1:3 18.0 9.30 × 10⁻⁴ >4.6Example 5-4 LiTFSI SN 1:1:3 19.2 1.28 × 10⁻³ >4.6 Example 5-5 LiPF₆ SN1:8:1 33.9 1.40 × 10⁻⁴ >4.6 Example 5-6 LiTFSI EC  8:82:10 1.78 8.20 ×10⁻⁴ >4.6 Example 5-7 LiTFSI EC 10:68:22 2.29 10.5 1.10 × 10⁻³ >4.6Example 5-8 LiTFSI EC 13:49:39 9.00 × 10⁻⁴ >4.6 Example 5-9 LiTFSI EC14:66:20 2.77 9.3 5.30 × 10⁻⁴ >4.6 Example 5-10 LiTFSI EC 13:74:13 3.2011.9 2.50 × 10⁻⁴ >4.6 Example 5-11 LiTFSI EC 16:64:20 1.52 × 10⁻⁴ >4.6Example 5-12 LiTFSI EC 28:55:17 5.2 1.20 × 10⁻⁴ >4.6 Example 5-13 LiTFSIEC 23:70:7 4.17 1.00 × 10⁻⁴ >4.6 Example 5-14 LiTFSI EC 52:37:11 7.21.10 × 10⁻⁴ >4.6 Example 5-15 LiTFSI EC 50:37:13 9.40 × 10⁻⁵ >4.6Example 5-16 LiTFSI EC 58:21:21 6.26 3.4 7.20 × 10⁻⁶ >4.6 Example 5-17LiTFSI EC 45:50:5  1.70 × 10⁻⁵ >4.6 Example 5-18 LiTFSI EC 70:23:7  8.042.5 2.10 × 10⁻⁶ >4.6

TABLE 3 Molar Ratio of De- Poly- com- mer: po- Ion In- Plasti- sitionTrans- Lithi- organic cizer: Tensile Po- fer um Plasti- Addi- LithiumStrength tential Num- Example Salt cizer tives Salt (MPa) (V) berExample LiTFSI SN Al₂O₃ 1:3:1 38.4 >4.6 0.64 5-19 (5% wt) Example Al₂O₃37.3 0.71 5-20 (10% wt) Example N/A 36.1 0.42 5-21 Example BaTiO₃ 39.20.77 5-22 (5% wt)

Cycling performance: The polymer solid electrolyte was assembled in a2032-coin cell with graphite as anode, and NMC811 as cathode. Thecycling test was performed with a Neware cycling tester. All thebatteries were tested using the same charging and discharging rate. Thecharge/discharge voltage window was from 2.8 V to 4.2 V. The battery wascycled at a current rate of 0.1 C from the first cycle to the fifthcycle, then the battery was cycled at a current rate of 0.33 C from thesixth cycle to the tenth cycle, then the battery was cycled at a currentrate of 0.5 C from the eleventh cycle to the fifteenth cycle, then thebattery was cycled at a current rate of 0.33 C from the sixteenth cycle.FIG. 8 illustrates the capacity retention curves of Example 5-2, Example5-22, and Comparison Example 1 at current rates of 0.1 C, 0.33 C, 0.5 C,0.33 C at room temperature.

From FIG. 8 , from the first cycle to the tenth cycle, ComparisonExample 1, Example 5-2, and Example 5-22 showed similar capacityretentions at >98% of a standard discharge capacity of 175 mAh/g at 0.1C and 0.33 C current rates. Comparison Example 1 and Example 5-2 showeda capacity retention of below 60% at a current rate of 0.5 C. Example5-22 showed a capacity retention of 70% at a current rate of 0.5 C.Thus, the formulation of Example 5-22 kept a 0.5 C rate capacityretention of 70% of its 0.1 C rate capacity retention. In contrast,Comparison Example 1 and Example 5-2 had capacity retentions both below60%, and the rate performance was improved by adding BaTO₃ as additive.

Comparing the capacity retention after cycling at 0.5 C (the capacityretention at a current rate of 0.33 C after the sixteenth cycle) and thecapacity retention before cycling at 0.5 C (the capacity retention at acurrent rate of 0.33 C from the sixth cycle to the tenth cycle),Comparison Example 1 showed reduced capacity retention after cycling at0.5 C, while Example 5-2 and Example 5-22 offered similar capacityretention, before and after cycling at 0.5 C. The cycling capacityretention of Example 5-2 and 5-22 was better than Comparison Example 1.Thus, the cycle performance of the polymer solid electrolyte wasimproved in this example.

In addition, in comparison with Example 5-2, Example 5-22 offered ahigher and more stable capacity retention. Cycle performance wasimproved by adding BaTO₃ as an additive.

FIG. 9 illustrates an ionic conductivity curve of the polymer solidelectrolyte of Example 5-22

The ionic conductivity of the electrolyte in Example 5-22 was 0.95×10⁻³S/cm. The inorganic additive BaTiO₃ increased the tensile strength to39.2 mPa, as can be seen by comparing these examples to Examples 5-19 to5-21. In addition, the ion transfer number also improved to 0.77.

The ion transfer number was measured using a Gamry 1010B or Gamry 1010Einstrument with a DC polarization of 10 mV, and an EIS spectrum in therange of 100 kHz to 1 Hz. The testing method was based on Peter G.Bruce, James Evants, and Colin A. Vincent, “Conductivity andtransference number measurements on polymer electrolytes,” Solid StateIonics, 28-30 (1988) 918-922.

Example 6

This example illustrates the synthesis of polyethylene glycol-bis-urea,Polymer G (see FIG. 3 ):

In this example, a round bottom flask was filled with poly(ethyleneglycol) diamine (40 mmol, Mn=2000, PEG2000DAm), 3-methyl-2-oxazolidinone(85 mmol), and chloroform (100 ml). The mixture was stirred for 24 hoursat 20° C. The resultant reaction mixture solution was washed with water(100 ml). The water fraction was separated and re-extracted by twoportions of chloroform (100 ml). All of the organic phases were combinedand dried with magnesium sulfate. The dried organic solution wasfiltered and concentrated using a rotary evaporator. A crude mixture ofpolyethylene glycol-bis-urea (PEGBU2000) was obtained as a yellow solid.The crude product was further purified by silica column chromatography.

The PEGBU2000 (10 mmol) obtained from last step was mixed withmethacrylic anhydride (25 mmol) in a beaker in an ice cold bath.4-dimethylaminopyridine (0.1%, DMAP) was used as a catalyst, withhydroquinone (0.1%, HQr) as an inhibitor, and triethylamine (50 mmol,TEA) was. The reaction was carried out for 24 hours. The crude reactionmixture was neutralized and washed with 0.5 M aqueous sodium bicarbonatesolution. Then, the aqueous phase was washed twice with chloroform. Allof the organic phases were combined and dried with magnesium sulfate.The dried organic solution was filtered and concentrated using a rotaryevaporator. A crude mixture of polyethylene glycol-bis-ureadimethacrylate (PEGBU2000DA) was obtained as a yellow solid. The crudeproduct was further purified by silica column chromatography with aneluent of mixed solvent of chloroform and n-hexane in a volume ratio ofbetween 1:4 and 3:2.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts, and plasticizer in the amountsand ratios described in Table 4 by mechanical stirring at roomtemperature in the liquid state.

The liquid and viscous mixture mentioned above was directly applied ontoa polyethylene terephthalate (PET) substrate. A 5-minute UV exposure wasapplied to the coating. Mechanical properties (e.g., tensile strengthand tensile elongation), ionic conductivities, and electrochemicalstability were determined. The measurement methods and conditions weresimilar to Example 1. The results are listed in Table 4.

Example 7

This example illustrates the synthesis of polypropyleneglycol-bis-carbamate, Polymer E (see FIG. 3 ):

In this structure, n is 45. In this example, a round bottom flask wasfilled with poly(propylene glycol) diamine (40 mmol, Mn=2000,PPG2000DAm), propylene carbonate (85 mmol), and chloroform (100 ml). Themixture was stirred for 24 hours at 20° C. The resultant reactionmixture solution was washed with water (100 ml). The water fraction wasseparated and re-extracted by two portions of chloroform (100 ml). Allof the organic phases were combined and dried with magnesium sulfate.The dried organic solution was filtered and concentrated using a rotaryevaporator. A crude mixture of polypropylene glycol-bis-carbamate(PPGBC2000) was obtained as a brown solid. The crude product was furtherpurified by silica column chromatography.

The PPGBC2000 (10 mmol) obtained from last step was mixed withmethacrylic anhydride (25 mmol) in a beaker in an ice cold bath.4-dimethylaminopyridine (0.1%, DMAP) was used as a catalyst, withhydroquinone (0.1%, HQr) as an inhibitor, and triethylamine (50 mmol,TEA). The reaction was carried out for 24 hours. The crude reactionmixture was neutralized and washed with 0.5 M aqueous sodium bicarbonatesolution. Then, the aqueous phase was washed twice with chloroform. Allof the organic phases were combined and dried with magnesium sulfate.The dried organic solution was filtered and concentrated using a rotaryevaporator. A crude mixture of polypropylene glycol-bis-carbamatedimethacrylate (PPGBC2000DA) was obtained as a yellow solid. The crudeproduct was further purified by silica column chromatography with aneluent of mixed solvent of chloroform and n-hexane in a volume ratio ofbetween 1:4 and 3:2.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts, and plasticizer in the amountsand ratios described in Table 4 by mechanical stirring at roomtemperature in the liquid state.

The liquid and viscous mixture mentioned above was directly applied ontoa polyethylene terephthalate (PET) substrate. A 5-minute UV exposure wasapplied to the coating. Mechanical properties (e.g., tensile strengthand tensile elongation), ionic conductivities, and electrochemicalstability were determined. The measurement methods and conditions weresimilar to Example 1. The results are listed in Table 4.

Example 8

This example illustrates the synthesis of polyphenylene-bis-carbamate,Polymer F (see FIG. 3 ):

In this structure, m is 45. In this example, a round bottom flask wasfilled with 1,4-phenylenediamine (40 mmol, Mn=2000, PDAm), propylenecarbonate (85 mmol), and chloroform (100 ml). The mixture was stirredfor 24 hours at 20° C. The resultant reaction mixture solution waswashed with water (100 ml). The water fraction was separated andre-extracted by two portions of chloroform (100 ml). All of the organicphases were combined and dried with magnesium sulfate. The dried organicsolution was filtered and concentrated using a rotary evaporator. Acrude mixture of polyphenylene-bis-carbamate (PPBC2000) was obtained abrown solid. The crude product was further purified by silica columnchromatography.

The PPBC2000 (10 mmol) obtained from the last step was mixed withmethacrylic anhydride (25 mmol) in a beaker in an ice cold bath.4-dimethylaminopyridine (0.1%, DMAP) was used as a catalyst, withhydroquinone (0.1%, HQr) as an inhibitor, and triethylamine (50 mmol,TEA). The reaction was carried out for 24 hours. The crude reactionmixture was neutralized and washed with 0.5 M aqueous sodium bicarbonatesolution. Then, the aqueous phase was washed twice with chloroform. Allthe organic phases were combined and dried with magnesium sulfate. Thedried organic solution was filtered and concentrated using a rotaryevaporator. A crude mixture of polyphenylene-bis-carbamatedimethacrylate (PPBC2000DA) was obtained as a yellow solid. The crudeproduct was further purified by silica column chromatography with aneluent of mixed solvent of chloroform and n-hexane in a volume ratio ofbetween 1:4 and 3:2.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts, and plasticizer in the amountsand ratios described in Table 4 by mechanical stirring at roomtemperature in the liquid state.

The liquid and viscous mixture mentioned above was directly applied ontoa polyethylene terephthalate (PET) substrate. A 5-minute UV exposure wasapplied to the coating. Mechanical properties (e.g., tensile strengthand tensile elongation), ionic conductivities, and electrochemicalstability were determined. The measurement methods and conditions weresimilar to Example 1. The results are listed in Table 4.

Comparison Example 3

This example illustrates the synthesis of polyethylene glycoldimethacrylate, Polymer D:

In this structure, n is 16. This polymer can be readily obtainedcommercially. In this example, the polyethylene glycol (10 mmol, Mn=700,PEG700) was mixed with methacrylic anhydride (25 mmol) in a beaker in anice cold bath. 4-dimethylaminopyridine (0.1%, DMAP) was used as acatalyst, with hydroquinone (0.1%, HQr) as an inhibitor, andtriethylamine (50 mmol, TEA). The reaction was carried out for 24 hours.The crude reaction mixture was neutralized and washed with 0.5 M aqueoussodium bicarbonate solution. Then the aqueous phase was washed twicewith chloroform. All of the organic phases were combined and dried withmagnesium sulfate. The dried organic solution was filtered andconcentrated using a rotary evaporator. A crude mixture of polyethyleneglycol dimethacrylate (PEGDA700) was obtained a yellow solid. The crudeproduct was further purified by silica column chromatography with aneluent of mixed solvent of chloroform and n-hexane in a volume ratio ofbetween 1:4 and 3:2.

A solid-state polymer electrolyte was obtained by mixing theas-synthesized polymer, lithium salts, and plasticizer in the amountsand ratios described in Table 4 by mechanical stirring at roomtemperature in the liquid state.

The liquid and viscous mixture mentioned above was directly applied ontoa polyethylene terephthalate (PET) substrate. A 5-minute UV exposure wasapplied to the coating. Mechanical properties (e.g., tensile strengthand tensile elongation), ionic conductivities, and electrochemicalstability were determined. The measurement methods and conditions aresimilar to Example 1. The results are listed in Table 4, and a graph ofstress versus strain of this polymer versus the one in Example 5 isshown in FIG. 1 . These were characterized using procedures similar tothose disclosed above in Example 1. The data were collected undersimilar methods and conditions.

Example Summary

Table 4 shows a comparison data set of Examples 5 through 8 using thesame measuring methods and conditions.

TABLE 4 Molar ratio of polymer: plasti- Elongation Ionic Decom- cizer:Tensile at Con- position Example/ Lithium Plasti- lithium strength breakductivity Voltage Comparison salt cizer salt (MPa) (%) (S/cm) (V)Example 5 LiTFSI SN 1:3:1 19.2 5.2 × 10⁻³ >4.6 Example 6 36.1 1.7 ×10⁻⁴ >4.6 Example 7 22.5 3.1 × 10⁻⁴ >4.6 Example 8 34.2 4.0 × 10⁻⁴ >4.6Comparison 8.2 1.3 × 10⁻⁴ 3.9 Example 3

Compared with Comparative Example 3, the polymer in Example 6 having aurea functional group exhibited increased tensile strength andelongation at break. The ionic conductivity was also improved. Inaddition, the urea functional group lead to a more stable material witha higher decomposition potential.

Compared with Comparative Example 3, the polymer in Examples 5, 7, and 8having a carbamate functional group exhibited increased tensile strengthand elongation at break. The ionic conductivity was also improved. Inaddition, the carbamate functional group lead to a more stable materialwith higher decomposition potential.

FIG. 4 illustrates electrochemical impedance spectroscopy of solid stateelectrolyte fabricated by the polymers in Examples 3, 4, 7, and 8, andComparison Examples 1 and 3. The formulation is shown in Table 1, 2 and3. The far left cross between the semi-cycle and the line Y=0 disclosethe bulk resistance of the solid state electrolyte membrane. The ionicconductivity can be calculated with the known thickness and area themembrane.

In summary, the incorporation of urea and/or carbamate functional groupswith UV crosslinked solidification appeared to considerably improvevarious mechanical properties and electrochemical performances. Thesepolymer solid electrolytes may help to achieve safe, long life lithiumsecondary batteries. The polymer solid electrolytes in these experimentsexhibited better ionic conductivity than the comparative materials, andthe lithium ion was conducted faster and more efficiently. Theseproperties may benefit the charging/discharging rate performances oflithium ion batteries. The improved decomposition potential of thepolymer materials can also provide enhanced stability in solid stateelectrolytes, which may provide longer life and/or higher voltagelithium batteries. In addition, the polymer solid electrolytes in theseexamples did not use any organic solvents. Thus, they may reliablyprovide safe performance of lithium ion batteries, as well as otherapplications.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe scope of the present invention.

In cases where the present specification and a document incorporated byreference include conflicting and/or inconsistent disclosure, thepresent specification shall control. If two or more documentsincorporated by reference include conflicting and/or inconsistentdisclosure with respect to each other, then the document having thelater effective date shall control.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.”

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

When the word “about” is used herein in reference to a number, it shouldbe understood that still another embodiment of the invention includesthat number not modified by the presence of the word “about.”

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

What is claimed is:
 1. An electrochemical cell with an electrolytecomprising a crosslinked polymer obtained by a crosslinking reactionincluding one or more monomers selected from the group consisting of:

wherein R₁ comprises a structure selected from the group consisting of:

wherein n is an integer between 1 and 10,000, inclusively; m is aninteger between 1 and 5,000, inclusively; R₂, R₃, R₄, R₅, and R₆ areeach independently selected from the group consisting of hydrogen,methyl, ethyl, phenyl, benzyl, acryl, epoxy ethyl, isocyanate, cycliccarbonate, lactone, lactam, and vinyl; and * indicates a point ofattachment.
 2. The electrochemical cell of claim 1, wherein the one ormore monomers are crosslinked in the presence of an initiator orcrosslinking agent, at an elevated temperature, under UV light, or acombination thereof.
 3. The electrochemical cell of claim 2, wherein theinitiator or crosslinking agent has a mole fraction ranging from 0.001and 0.01.
 4. The electrochemical cell of claim 1, wherein theelectrolyte comprises a plasticizer and an electrolyte salt.
 5. Theelectrochemical cell of claim 4, wherein the one or more monomers have amole fraction ranging from 0.027 to 0.200 in the electrolyte prior tothe crosslinking, the plasticizer has a mole fraction ranging from 0.287to 0.916, and the electrolyte salt has a mole fraction ranging from 0.04to 0.617.
 6. The electrochemical cell of claim 4, wherein theplasticizer comprises ethylene carbonate, cyclic carbonate, oligoether,succinonitrile, polyethylene oxide, polycarbonate, polyacrylonitrile,polyactic acid, ionic liquid, nitrile or a combination thereof.
 7. Theelectrochemical cell of claim 4, wherein the electrolyte salt comprisesa lithium salt, a quaternary ammonium salt, a quaternary phosphoniumsalt, a transition metal salt, or a salt of protonic acid.
 8. Theelectrochemical cell of claim 4, wherein the electrolyte is a solidpolymer electrolyte and has a tensile strength of between 5 and 500 MPa.9. The electrochemical cell of claim 4, wherein the electrolyte has anionic conductivity of between 1.0×10⁻⁸ and 1.0×10⁻² S/cm and adecomposition voltage of at least 3.8 V.
 10. The electrochemical cell ofclaim 1, wherein the electrochemical cell is a battery, a lithium-ionbattery or a solid state battery.
 11. The electrochemical cell of claim4, wherein the one or more monomers are crosslinked after mixing withthe electrolyte salt and the plasticizer.
 12. The electrochemical cellof claim 1, wherein the electrolyte further comprises an inorganicadditive.
 13. The electrochemical cell of claim 12, wherein theinorganic additive is selected from the group consisting of Al₂O₃, SiO₂,SiO_(x), TiO₂, Li₃PS₄, Li₁₀GeP₂S₁₂, Li₇La₃Zr₂O₁₂,Li_(6.4)La₃Zr_(1.4)Ta_(0.6)O₁₂, LiLaTiO₃,Li_(1.3)Al_(0.3)Ti_(1.7)(PO₄)₃, Li_(1.3)Al_(0.3)Ge_(1.7)(PO₄)₃, ZrO₂,BaTiO₃ and Li₂TiO₃.
 14. The electrochemical cell of claim 1, wherein thecrosslinked polymer is formed via urea and/or carbamate functionalgroups.
 15. An electrochemical cell with an electrolyte comprising acrosslinked copolymer obtained by a crosslinking reaction including afirst monomer selected from the group consisting of:

and a second monomer selected from the group consisting of methacrylate,norbornyl methacrylate, methyl methacrylate, ethyl methacrylate, butylmethacrylate, 2-aminoethyl methacrylate hydrochloride, glycidylmethacrylate, 2-(diethylamino)ethyl methacrylate, wherein R₁ comprises astructure selected from the group consisting of:

wherein n is an integer between 1 and 10,000, inclusively; m is aninteger between 1 and 5,000, inclusively; R₂, R₃, R₄, R₅, and R₆ areeach independently selected from the group consisting of hydrogen,methyl, ethyl, phenyl, benzyl, acryl, epoxy ethyl, isocyanate, cycliccarbonate, lactone, lactam, and vinyl; and * indicates a point ofattachment.
 16. A method of making a solid electrolyte comprising acrosslinked polymer, comprising: a) mixing a composition comprising oneor more monomers, an electrolyte salt and a plasticizer to form aslurry; and b) curing the one or more monomers in the slurry into acrosslinked polymer, leading to a solid electrolyte comprising thecrosslinked polymer with the electrolyte salt and plasticizer therein,wherein the one or more monomers are selected from the group consistingof:

wherein R₁ comprises a structure selected from the group consisting of:

wherein n is an integer between 1 and 10,000, inclusively; m is aninteger between 1 and 5,000, inclusively; R₂, R₃, R₄, R₅, and R₆ areeach independently selected from the group consisting of hydrogen,methyl, ethyl, phenyl, benzyl, acryl, epoxy ethyl, isocyanate, cycliccarbonate, lactone, lactam, and vinyl; and * indicates a point ofattachment.
 17. The method of claim 16, wherein the slurry is cured inthe presence of an initiator or crosslinking agent, under UV, or in thepresence of an initiator or crosslinking agent under UV.
 18. The methodof claim 16, wherein the slurry is cured at a temperature between 20° C.and 100° C.
 19. The method of claim 16, further comprising, forming afilm of the slurry prior to curing the slurry.
 20. The method of claim16, wherein the composition comprises a solvent and the solvent isremoved after formation of the slurry.